diff --git a/plugins/disk/du-2 b/plugins/disk/du-2
index 16bd1873..39787e50 100755
--- a/plugins/disk/du-2
+++ b/plugins/disk/du-2
@@ -5,10 +5,9 @@
 
   du - Plugin to monitor multiple directories size
 
-=head1 AUTHOR
+=head1 AUTHOR AND COPYRIGHT
 
-  Luc Didry <luc AT didry.org>
-  April 2011
+  Copyright 2011-2012 Luc Didry <luc AT didry.org>
 
 =head1 HOWTO CONFIGURE AND USE :
 
@@ -44,6 +43,21 @@
   #%# family=auto
   #%# capabilities=autoconf
 
+=head1 LICENSE
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 =cut
 
 use warnings;
@@ -99,7 +113,7 @@ while(defined (my $foo = <FILE>)) {
     if ($foo =~ m/(\d+)\s+(.+)/) {
         my ($field, $value) = ($2, $1);
         clean_path(\$field);
-        print $field, ".value ", $value, "\n"; 
+        print $field, ".value ", $value, "\n";
     }
 }
 close(FILE);
@@ -107,7 +121,7 @@ daemonize();
 
 #
 ##
-### PUBLiC FONCTiONS
+### PUBLIC FONCTIONS
 ###############################################################################
 ## Used to create the fork
 sub daemonize {
@@ -135,7 +149,7 @@ sub clean_path {
     }
 } ## clean_path
 
-## Do you really need I told you what this function is going to check ?
+## Do you really need I told you what this functions are going to check ?
 sub cache_is_too_old {
     return 1 if (! -e $TIMEFILE);
     my ($time) = `cat $TIMEFILE`;
@@ -145,21 +159,33 @@ sub cache_is_too_old {
 } ## cache_is_too_old
 
 sub du_not_running {
-	return 0 if (-e $LOCKFILE);
-	return 1;
+    if (-e $LOCKFILE) {
+        my ($time) = `cat $TIMEFILE`;
+        chomp $time;
+        if ( (time - $time) > ($ENV{interval}*60*60) ) {
+            # The cache is really old (60xinterval) => Maybe the lockfile wasn't properly deleted.
+            # Let's delete it.
+            system("rm $LOCKFILE;");
+            return 1;
+        } else {
+	        return 0;
+        }
+    } else {
+        return 1;
+    }
 }
+
 sub munin_exit_done {
     __munin_exit(0);
 } ## sub munin_exit_done
 
-
 sub munin_exit_fail {
     __munin_exit(1);
 } ## sub munin_exit_fail
 
 #
 ##
-### iNTERNALS FONCTiONS
+### INTERNALS FONCTIONS
 ###############################################################################
 sub __munin_exit {
     my $exitcode = shift;